I am adding this in case someone does a search for this question. JWs entire belief system hinges on this date. Any JW reading this: If you don't believe me, then prove it. Please! Read God's Word. Are we not to test the inspired expressions? Where was Christ in 1879? 1914? 1919? Where do the JWs say that he was? LOOK! God's Word will set you free!

Matthew 24:23 Then if anyone says to you, Ã¢â‚¬ËœBehold, here is the [l]Christ,Ã¢â‚¬â„¢ or Ã¢â‚¬Ëœ[m]There He is,Ã¢â‚¬â„¢ do not believe him. 24 For false Christs and false prophets will arise and will [n]show great [o]signs and wonders, so as to mislead, if possible, even the [p]elect. 25 Behold, I have told you in advance. 26 So if they say to you, Ã¢â‚¬ËœBehold, He is in the wilderness,Ã¢â‚¬â„¢ do not go out, or, Ã¢â‚¬ËœBehold, He is in the inner rooms,Ã¢â‚¬â„¢ do not believe them. 27 For just as the lightning comes from the east and flashes even to the west, so will the coming of the Son of Man be.

I am adding this in case someone does a search for this question. JWs entire belief system hinges on this date. Any JW reading this: If you don't believe me, then prove it. Please! Read God's Word. Are we not to test the inspired expressions? Where was Christ in 1879? 1914? 1919? Where do the JWs say that he was? LOOK! God's Word will set you free!

Matthew 24:23 Then if anyone says to you, ‘Behold, here is the [l]Christ,’ or ‘[m]There He is,’ do not believe him. 24 For false Christs and false prophets will arise and will [n]show great [o]signs and wonders, so as to mislead, if possible, even the [p]elect. 25 Behold, I have told you in advance. 26 So if they say to you, ‘Behold, He is in the wilderness,’ do not go out, or, ‘Behold, He is in the inner rooms,’ do not believe them. 27 For just as the lightning comes from the east and flashes even to the west, so will the coming of the Son of Man be.

From memory only--all the sources that I read in Bible college, it was 538 BC. There was the fall of the northern kingdom earlier, and then the fall of Judah (Jerusalem). I learned about the seventy weeks of Daniel, which is central to the foundational teaching about the antichrist, the great tribulation, etc.

But as far as your belief system "hinging" on a date--makes it suspect anyway. Eschatology (last day doctrine) should not be central to the faith, but the cross of Christ. The hope of being with Christ in the end is important, but it is not the foundation. Nothing is to hinge on the result, but the cause--which is Christ and him crucified. 1 Corinthians 1:23

Matthew 24:23“Then if anyone tells you, ‘Look, here is the Messiah,’ or ‘There he is,’ don’t believe it. 24 For false messiahs and false prophets will rise up and perform great signs and wonders so as to deceive, if possible, even God’s chosen ones. 25 See, I have warned you about this ahead of time.

26 “So if someone tells you, ‘Look, the Messiah is out in the desert,’ don’t bother to go and look. Or, ‘Look, he is hiding here,’ don’t believe it! 27 For as the lightning flashes in the east and shines to the west, so it will be when the Son of Man[a] comes.